In recent years, a display apparatus such as a liquid crystal display apparatus has widely been spread. The liquid crystal display apparatus is constituted by a liquid crystal panel and a backlight (light source device). In the liquid crystal display apparatus, one surface of the liquid crystal panel is irradiated with light from the backlight so that an image is displayed on the other surface. The backlight serves to planarly propagate the light from a light source unit through the inside thereof. The backlight includes a light guide plate having the shape of a rectangular plate emitting light from one main surface, a reflection sheet layered on the other main surface of the light guide plate, an optical sheet composed of multiple sheets for making the light emitted from the light guide plate into a uniform luminance distribution, and a backlight chassis having the shape of a rectangular parallelepiped box with one face being open. The backlight chassis houses the light source unit, light guide plate, reflection sheet and optical sheet.
The reflection sheet is held between the light guide plate and the backlight chassis.
In recent years, the size of the backlight chassis has been increased as the display apparatus is made larger. A large backlight chassis is generally fabricated by sheet-metal working of a steel plate in view of its strength and cost. Such a large backlight chassis is fabricated by dividing a steel plate into multiple members and then connecting the members together in order to prevent so-called oil canning which may cause abnormal noise (chattering noise) when vibrated and to facilitate the working